C-看门狗定时器未启动或未调用回调函数

Question

I am creating a VxWorks program using the Wind River Workbench 3.3.

The program requires me to make use of Watchdog Timers, however I am having problems in getting the timers to start.

Below is a snippet of some of my code. As you can see in the main function I create my Watchdog Timer (wdCreate()) and the timer is started in the smallObject function (wdStart()). I have verified that my code does indeed reach the smallObject function as intended.

I have set the call-back function of the timer to the function called closeOpenGates(), however the timer never calls back to this function after any amount of time.

I have included the necessary header file '#include "wdLib.h".

#include "vxWorks.h"
#include "sysLib.h"
#include "taskLib.h"
#include "stdio.h"
#include "stdlib.h"
#include "cinterface.h"
#include "semLib.h"
#include "wdLib.h"
#include “msgQLib.h”

SEM_ID smallObjectSem;
SEM_ID largeObjectSem;

WDOG_ID gateTimer; /* Gate timer */ 
int gateTimerI

void main (void)
{
    char sizeSensorState;
    int res;

    startMotor(); /* Begins the motor to turn the conveyors */

    /* Create the task for handling detected small objects */
    int smallObjectTask;
    smallObjectTask = taskSpawn("Small Object Task", 100, 0, 20000, (FUNCPTR)smallObject, 0,0,0,0,0,0,0,0,0,0);


    gateTimer = wdCreate(); /* Create a timer for when to close the gate */
    if (gateTimer == NULL) 
    {
        printf("\n\nCannot create the gate timer! Terminating task...\n");
        exit(0);
    }

void smallObject(void)
{
    while (1)
    {

        smallObjectDetect0++; /* Increase the detected small object count by 1 */



        /* Start a timer for 3.5s - how long it takes the object to reach the gates */ 
        gateTimerInt = wdStart(gateTimer, 3.5 * sysClkRateGet(), (FUNCPTR)closeOpenGate, 0);
        if (gateTimerInt == ERROR)
        {
            printf("Cannot start the gate timer! Terminating task...");
            exit(0);
        }
        else printf("\nTimer started successfully");    
    }
}

void closeOpenGate (void)
{
    printf("\n Small Timer Successful");

    setGates(1); /* Close the gate on Conveyor 0 */
    taskDelay(1.5 * sysClkRateGet()); /* Wait for 1.5s to allow the small object to fall off */
    setGates(0); /* Reopen the gate */  
}

Any ideas about what might be causing my Watchdog Timer to not start or call-back to the function will be greatly appreciated.

Many thanks.

Answer 1

The main problem here is you are constantly restarting the timer, inside your task. smallObject executes an infinite loop, and on each occasion calls wdStart. The only time it will not do so, is if the call to wdStart fails, in which case the task will exit.

Calling wdStart on a timer that is already running, has the effect of restarting the timer. Thus, it is constantly restarted, and thus never timesout.

Answer 2

您将wdStart（）放入while循环中，这导致它始终调用它，并且WatchDog计时器没有机会超时。